Oceanography and Atmospheric Sciences and Meteorology Commons^™

Investigating The Atmospheric Production Of Perchlorate: Inference From Polar Ice Cores, Thomas S. Cox

Electronic Theses and Dissertations

Perchlorate (ClO₄) in the environment is of concern, because of potential health risks to humans, among other reasons. Evidence suggests that the majority of environmental perchlorate is formed in the atmosphere (likely in the stratosphere), in chemical processes involving ozone and stratospheric chlorine. A lack of knowledge in regards to the processes has resulted in a limited understanding of the environmental conditions and variables that influence perchlorate production and consequently perchlorate prevalence and variability in the environment. In this study, perchlorate was measured, using an established ion chromatography-­‐electrospray ionization-­‐tandem mass spectrometry (IC-­‐ESI-­‐ MS/MS) technique, in over 1,600 snowpit …

Quantification Of Urban Atmospheric Boundary Layer Greenhouse Gas Dry Mole Fraction Enhancements In The Dormant Season: Results From The Indianapolis Flux Experiment (Influx), Natasha Miles, Scott Richardson, Thomas Lauvaux, Kenneth J. Davis, Nikolay V. Balashov, Aijun Deng, Jocelyn Turnbull, Colm Sweeney, Kevin R. Gurney, Risa Patarasuk, Igor Razlivanov, Maria Obiminda L. Cambaliza, Paul B. Shepson

Physics Faculty Publications

We assess the detectability of city emissions via a tower-based greenhouse gas (GHG) network, as part of the Indianapolis Flux (INFLUX) experiment. By examining afternoon-averaged results from a network of carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) mole fraction measurements in Indianapolis, Indiana for 2011–2013, we quantify spatial and temporal patterns in urban atmospheric GHG dry mole fractions. The platform for these measurements is twelve communications towers spread across the metropolitan region, ranging in height from 39 to 136 m above ground level, and instrumented with cavity ring-down spectrometers. Nine of the sites were deployed as of January …

Metagomics: A Web-Based Tool For Peptide-Centric Functional And Taxonomic Analysis Of Metaproteomics Data, Michael Riffle, Damon H. May, Emma Timmins-Schiffman, Molly P. Mikan, Daniel Jaschob, William S. Noble, Brook L. Nunn

OES Faculty Publications

Metaproteomics is the characterization of all proteins being expressed by a community of organisms in a complex biological sample at a single point in time. Applications of metaproteomics range from the comparative analysis of environmental samples (such as ocean water and soil) to microbiome data from multicellular organisms (such as the human gut). Metaproteomics research is often focused on the quantitative functional makeup of the metaproteome and which organisms are making those proteins. That is: What are the functions of the currently expressed proteins? How much of the metaproteome is associated with those functions? And, which microorganisms are expressing the …

Widespread Infilling Of Tidal Channels And Navigable Waterways In The Human-Modified Tidal Deltaplain Of Southwest Bangladesh, C. Wilson, S. Goodbred, C. Small, J. Gilligan, S. Sams, B. Mallick, R. Hale

OES Faculty Publications

Since the 1960s, ~5000 km² of tidal deltaplain in southwest Bangladesh has been embanked and converted to densely inhabited, agricultural islands (i.e., polders). This landscape is juxtaposed to the adjacent Sundarbans, a pristine mangrove forest, both well connected by a dense network of tidal channels that effectively convey water and sediment throughout the region. The extensive embanking in poldered areas, however, has greatly reduced the tidal prism (i.e., volume of water) transported through local channels. We reveal that >600 km of these major waterways have infilled in recent decades, converting to land through enhanced sedimentation and the direct blocking …

Upper Water Structure And Mixed Layer Depth In Tropical Waters: The Seats Station In The Northern South China Sea, Jen-Hua Tai, George T. F. Wong, Xiaoju Pan

OES Faculty Publications

The variability of the upper water hydrographic structure, the efficacy of the different schemes for estimating the mixed layer depth (MLD), the inter-comparability estimation of the MLDs and diurnal and intra-annual MLD climatology in the tropical waters in the northern South China Sea were accessed in 702 depth-profiles of potential temperature (θ) and salinity collected in 64 cruises between 17.5 and 18.5°N and 115.3 and 116.3°E from 1997 to 2013. The hydrographic structure may be subdivided into three principal types: the classical type, with quasi-isopycnal surface mixed layer followed by an abrupt increase in the depth-gradient in θ and potential …

Spatial Patterns Of Sea Level Variability Associated With Natural Internal Climate Modes, Weiqing Han, Gerald A. Meehl, Detlef Stammer, Aixue Hu, Benjamin Hamlington, Jessica Kenigson, Hindumathi Palanisamy, Philip Thompson

OES Faculty Publications

Sea level rise (SLR) can exert significant stress on highly populated coastal societies and low-lying island countries around the world. Because of this, there is huge societal demand for improved decadal predictions and future projections of SLR, particularly on a local scale along coastlines. Regionally, sea level variations can deviate considerably from the global mean due to various geophysical processes. These include changes of ocean circulations, which partially can be attributed to natural, internal modes of variability in the complex Earth's climate system. Anthropogenic influence may also contribute to regional sea level variations. Separating the effects of natural climate modes …

Eukaryotic Microbes, Principally Fungi And Labyrinthulomycetes, Dominate Biomass On Bathypelagic Marine Snow, Alexander B. Bochdansky, Melissa A. Clouse, Gerhard J. Herndl

OES Faculty Publications

In the bathypelagic realm of the ocean, the role of marine snow as a carbon and energy source for the deep-sea biota and as a potential hotspot of microbial diversity and activity has not received adequate attention. Here, we collected bathypelagic marine snow by gentle gravity filtration of sea water onto μm filters from similar to 1000 to 3900 m to investigate the relative distribution of eukaryotic microbes. Compared with sediment traps that select for fast-sinking particles, this method collects particles unbiased by settling velocity. While prokaryotes numerically exceeded eukaryotes on marine snow, eukaryotic microbes belonging to two very distant …

Elevated Trace Metal Content Of Prokaryotic Communities Associated With Marine Oxygen Deficient Zones, Daniel C. Ohnemus, Sara Rauschenberg, Gregory A. Cutter, Jessica N. Fitzsimmons, Robert M. Sherrell, Benjamin S. Twining

OES Faculty Publications

Little is known about the trace metal content of marine prokaryotes, in part due to their co-occurrence with more abundant particulate phases in the upper ocean, such as phytoplankton and biogenic detritus, lithogenic minerals, and authigenic Mn and Fe oxyhydroxides. We attempt to isolate these biomass signals in particulate data from the US GEOTRACES Eastern Pacific Zonal Transect (cruise GP16) in the Eastern Tropical South Pacific (ETSP), which exhibited consistent maxima in P and other bioactive trace metals, and minima in particulate Mn, in the oxygen deficient zones (ODZs) of 13 stations. Nitrite maxima and nitrate deficits indicated the presence …

Critical Decisions In Metaproteomics: Achieving High Confidence Protein Annotations In A Sea Of Unknowns, Emma Timmins-Schiffman, Damon H. May, Molly Mikan, Michael Riffle, Chris Frazar, H. R. Harvey, William S. Noble, Brook L. Nunn

OES Faculty Publications

No abstract provided.

Effects Of Climate Oscillations On Wildland Fire Potential In The Continental United States, Shelby A. Mason, Peter E. Hamlington, Benjamin D. Hamlington, W. Matt Jolly, Chad M. Hoffman

OES Faculty Publications

The effects of climate oscillations on spatial and temporal variations in wildland fire potential in the continental U.S. are examined from 1979 to 2015 using cyclostationary empirical orthogonal functions (CSEOFs). The CSEOF analysis isolates effects associated with the modulated annual cycle and the El Nino-Southern Oscillation (ENSO). The results show that, in early summer, wildland fire potential is reduced in the southwest during El Nino but is increased in the northwest, with opposite trends for La Nina. In late summer, El Nino is associated with increased wildland fire potential in the southwest. Relative to the mean, the largest impacts of …

Community Production Modulates Coral Reef Ph And The Sensitivity Of Ecosystem Calcification To Ocean Acidification, Thomas M. Decarlo, Anne L. Cohen, George T. F. Wong, Fuh-Kwo Shiah, Steven J. Lentz, Kristen A. Davis, Kathryn E. F. Shamberger, Pat Lohmann

OES Faculty Publications

Coral reefs are built of calcium carbonate (CaCO₃) produced biogenically by a diversity of calcifying plants, animals, and microbes. As the ocean warms and acidifies, there is mounting concern that declining calcification rates could shift coral reef CaCO3 budgets from net accretion to net dissolution. We quantified net ecosystem calcification (NEC) and production (NEP) on Dongsha Atoll, northern South China Sea, over a 2 week period that included a transient bleaching event. Peak daytime pH on the wide, shallow reef flat during the nonbleaching period was ~8.5, significantly elevated above that of the surrounding open ocean (~8.0-8.1) as …

Twenty-First Century Climate Change And Submerged Aquatic Vegetation In A Temperate Estuary: The Case Of Chesapeake Bay, Thomas M. Arnold, Richard C. Zimmerman, Katharina A.M. Engelhardt, J. Court Stevenson

OES Faculty Publications

Introduction: The Chesapeake Bay was once renowned for expansive meadows of submerged aquatic vegetation (SAV). However, only 10% of the original meadows survive. Future restoration effortswill be complicated by accelerating climate change, including physiological stressors such as a predicted mean temperature increase of 2-6°C and a 50-160% increase in CO2 concentrations.

Outcomes: As the Chesapeake Bay begins to exhibit characteristics of a subtropical estuary, summer heat waves will become more frequent and severe. Warming alone would eventually eliminate eelgrass (Zostera marina) from the region. It will favor native heat-tolerant species such as widgeon grass (Ruppia maritima) while facilitating colonization by …

Impact Of Glacial/Interglacial Sea Level Change On The Ocean Nitrogen Cycle, Haojia Ren, Daniel M. Sigman, Alfredo Martínez-García, Robert F. Anderson, Chen Min-Te, Ana Christina Ravelo, Marietta Straub, George T. F. Wong, Gerald H. Haug

OES Faculty Publications

The continental shelves are the most biologically dynamic regions of the ocean, and they are extensive worldwide, especially in the western North Pacific. Their area has varied dramatically over the glacial/interglacial cycles of the last million years, but the effects of this variation on ocean biological and chemical processes remain poorly understood. Conversion of nitrate to N2 by denitrification in sediments accounts for half or more of the removal of biologically available nitrogen ("fixed N") from the ocean. The emergence of continental shelves during ice ages and their flooding during interglacials have been hypothesized to drive changes in sedimentary denitrification. …

Phytoplankton Plastid Proteomics: Cracking Open Diatoms To Understand Plastid Biochemistry Under Iron Limitation, Skyler J. Nunn, Phoebe Dreux Chappell, Kristofer Gomes, Anasthasia Bonderenko, Bethany D. Jenkins, Brook L. Nunn

OES Faculty Publications

Diatoms, such as Thalassiosira pseudonana, are important oceanic primary producers, as they sequester carbon dioxide (CO₂) out of the atmosphere, die, and precipitate to the ocean floor. In many areas of the world’s oceans, phytoplankton, such as diatoms, are limited in growth by the availability of iron (Fe). Fe is an essential nutrient for phytoplankton, as it is central in the electron transport chain component of photosynthesis. Through this study, we examined if Fe-limitation makes a significant difference in the proteins expressed within the chloroplast, the power source for diatoms. Here, we utilized a new plastid isolation technique specific …

Language Learning Under Classroom Conditions During The Transition To Hybrid Instruction: A Case-Study Of Student Performance During The Implementation Of Instructional Technology, Lisbeth O. Swain, Timothy D. Swain

Marine & Environmental Sciences Faculty Articles

We examined the unmanipulated performance of students under real classroom conditions in order to assess the effect of a technology-enhanced hybrid learning approach to second language, (L2) instruction on beginning and advanced Spanish language learners. This research focused on the transition period of technology implementation when the entire section of Spanish of a modern language department of a liberal arts university transitioned from traditional face-to-face instruction, to a technology-enhanced hybrid learning approach with concurrent reduction in face-to-face classroom hours. This implementation provided an opportunity to compare the performance of students prior to and during the transition to hybrid model of …

Heterogeneous Nitrogen Losses: Cost-Effectiveness Analysis Of Changes In Management Across South Dakota, Archibold Quaye

Electronic Theses and Dissertations

The loss of nitrogen fertilizer into the atmosphere and waterways is of increasing concern for citizens and policy makers. This is particularly relevant for hypoxia in rivers, lakes, and oceans, but also relevant for policy makers in reducing the increasing concentration of greenhouse gases (GHG) in the atmosphere. GHGs trap heat in the atmosphere and include: carbon dioxide, methane, nitrous oxide and fluorinated gases. Overall, the estimated contribution from the agricultural sector to GHG emissions was 9% in 2013 (EPA, 2013). Further, the addition of nitrogen to the soil through the use of synthetic fertilizers is a main contributor to …

Flooding And Inundation Modeling In The Great Bay Estuary, Anna E. Simpson

Honors Theses and Capstones

As part of this research, FVCOM, a finite-volume coastal ocean numerical hydrodynamic model (Chen, et al., 2003), was implemented into the Great Bay estuary. FVCOM is one of several community models that have been developed for coastal regions, and was selected because it utilizes an unstructured grid to discretize the model domain. The unstructured grid provides the ability to have fine scale resolution near the boundary or coastline and decreased resolution away from the boundary where the flow field is less complicated, resulting in greatly reduced computational expense in less dynamic regions allowing model runs to be completed in …

Studies Of Direct Solar Irradiance And Aerosol Optical Depth Using An Mfrsr And A Microtop Sunphotometer In The El Paso-Juarez Airshed, Arjun Aryal

Open Access Theses & Dissertations

The study of Solar Irradiance and Aerosol Optical Depth (AOD) plays an important role in understanding the regional and global climate distribution, and is also important in air pollution studies. In this work an MFRSR (Multi-Filter Rotating Shadowband Radiometer) and a Portable Microtop Sunphotometer were used to measure irradiances and to obtain optical depth values for the El Paso-Juarez Airshed. The Langley method applied on the MFRSR irradiance data was used to calculate the AOD values. The spatial distribution of AOD for this region was obtained using a Microtop Sunphotometer. The graphs were generated using GIS Shapefiles. In addition, the …

Spaceborne Synthetic Aperture Radar Survey Of Subsidence In Hampton Roads, Virginia (Usa), D.P.S. Bekaert, B. D. Hamlington, B. Buzzanga, C. E. Jones

CCPO Publications

Over the past century, the Hampton Roads area of the Chesapeake Bay region has experienced one of the highest rates of relative sea level rise on the Atlantic coast of the United States. This rate of relative sea level rise results from a combination of land subsidence, which has long been known to be present in the region, and rising seas associated with global warming on long timescales and exacerbated by shifts in ocean dynamics on shorter timescales. An understanding of the current-day magnitude of each component is needed to create accurate projections of future relative sea level rise upon …

A Climatological And Multiscale Analysis Of Cold Air Outbreaks In The Northeast United States, Zachary Baker Murphy

Legacy Theses & Dissertations (2009 - 2024)

The results of a climatological and multiscale analysis of cold air outbreaks (CAOs) that impacted the Northeast U.S. during 1948–2015 are presented. This climatological and multiscale analysis was based on daily minimum temperature data extracted from the National Centers for Environmental Information (NCEI) Global Historical Climatology Network-Daily dataset for 53 stations that were distributed throughout nine climate regions defined by the NCEI. A CAO is diagnosed whenever two or more stations within an NCEI climate region experience three or more consecutive days where the daily minimum temperatures at a station fall below the 31-day centered moving average of the fifth …

Understanding Climatic Adjustments To Variations In Tropical Ocean Heat Transport, Michael Cameron Rencurrel

Legacy Theses & Dissertations (2009 - 2024)

One of the outstanding problems within the climate community has been how to reconcile the geological proxy records of past warm, equable climates, characterized by both an increase in the global mean surface temperature and a decrease in the equator-to-pole temperature gradient, with numerical simulations of the same period. Recent work has shown that tectonic driven changes in the meridional ocean heat transport (OHT) may have played a signicant role in the warming. Here, we study the adjustment of the climate to variations in OHT using a suite of slab-ocean aquaplanet GCM simulations spanning 24 different imposed variations in OHT …

Hurricane Bonnie (1998) : Maintaining Intensity During High Vertical Wind Shear And An Eyewall Replacement Cycle, Erin Dougherty

Legacy Theses & Dissertations (2009 - 2024)

Hurricane Bonnie (1998) was an unusually resilient hurricane that maintained intensity in 12–16 ms-1 vertical wind shear and during an eyewall replacement cycle from 23 – 25 August. This remarkable behavior was examined using observations from flight-level data, microwave imagery, radar, and dropsondes over the two-day period. The symmetric and asymmetric aspects of Bonnie’s eyewall replacement cycle were documented and compared to eyewall replacement cycles in other hurricanes. Similar to other observed eyewall replacement cycles, Bonnie exhibited the development, strengthening, and dominance of a secondary eyewall while a primary eyewall decayed. However, Bonnie’s structure was highly asymmetric due to strong …

A Synoptic Climatology Of Combined Severe/Weather/Flash Flood Events, Kyle James Pallozzi

Legacy Theses & Dissertations (2009 - 2024)

Classical forms of severe weather such as tornadoes, damaging convective wind gusts, and large hail, as well as flash flooding events, all have potentially large societal impacts. This impact is further magnified when these hazards occur simultaneously in time and space. A major challenge for operational forecasters is how to accurately predict the occurrence of combined storm hazards, and how to communicate the associated multiple threat hazards to the public. A seven-year climatology (2009-2015) of combined severe weather/flash flooding (SVR/FF) events across the contiguous United States was developed in attempt to study the combined SVR/FF event hazards further.

Rossby Wave Breaking And Widespread Extreme Precipitation Events In The Central And Eastern U.S, Benjamin John Moore

Legacy Theses & Dissertations (2009 - 2024)

This dissertation examines climatological and dynamical linkages between widespread extreme precipitation events (EPEs) in the central and eastern U.S. and Rossby wave breaking (RWB), and assesses forecast skill for EPEs occurring in conjunction with RWB. The analysis primarily focuses on linkages of EPEs to LC1 (anticyclonic) and LC2 (cyclonic) RWB.

Ensemble Variability In Rainfall Forecasts Of Hurricane Irene (2011), Molly Becker Smith

Legacy Theses & Dissertations (2009 - 2024)

As tropical cyclones (TCs) move into the midlatitudes, they are often associated with extensive heavy precipitation. This precipitation can lead to widespread flooding events, such as occurred with Hurricane Irene (2011) over the northeastern United States. Despite the high-impact nature of these events, there are relatively few studies that explore the sensitivity of precipitation forecasts to model initial conditions, beyond focusing on the variability in forecast TC track.

Influence Of Volcanic Eruptions On Tropical Hydroclimate During The Last Millennium, Christopher Colose

Legacy Theses & Dissertations (2009 - 2024)

Volcanic eruptions exert the most important radiative forcing on Earth’s climate during the pre-industrial interval of the last millennium. In this thesis, I investigate the role of volcanic eruptions in altering tropical climate, including temperature and rainfall. I primarily use forced transient simulations of the last millennium as a tool to explore how explosive volcanic events project onto the hydrologic cycle, as well as the imprint of water isotopologues (H216O, H218O) associated with rainfall. Attention is given to the South American continent specifically (in chapter 2), and to the entire tropics (in chapter 3).

Climate Fingerprints Of The Interdecadal Pacific Oscillation, Bo Dong

Legacy Theses & Dissertations (2009 - 2024)

The Interdecadal Pacific Oscillation (IPO) is a multi-decadal quasi-oscillation seen primarily in tropical and extratropical Pacific sea surface temperatures (SSTs). Interacting with the atmosphere, the IPO has been shown to affect global and regional climate. However, a quantitative global synthesis of the IPO’s climate fingerprints and the underlying mechanisms are still lacking. Based on observational and reanalysis data and atmospheric model simulations, this dissertation investigates the IPO’s influence on regional climates over the globe, and its interactions with El Niño-Southern Oscillation (ENSO) and global warming.

Turbulence In The Upper Levels Of Tropical Cyclones, Michaela Leigh Rosenmayer

Legacy Theses & Dissertations (2009 - 2024)

Turbulence in the cirrus canopy of tropical cyclones (TCs) can give an indication about the physical processes that occur in this expansive cloud deck. The low stability and/or large shear that likely coincides with turbulent layers can be produced by radiative forcing, convective forcing, and sublimation of frozen precipitation from the cirrus canopy. As a result, turbulence in the cirrus canopy can give an indication about the impact of various physical processes in tropical cyclones.

A Multiscale Analysis Of Major Transition Season Northeast Snowstorms, Rebecca Blair Steeves

Legacy Theses & Dissertations (2009 - 2024)

Major transition season Northeast snowstorms have the potential to cause widespread socioeconomic disruption in the form of transportation delays, infrastructure damage, and widespread power outages. Because heavy, wet snow tends to occur in transition season Northeast snowstorms, lesser accumulations can result in greater disruption than if the same accumulation occurred in winter season Northeast snowstorms. This study is motivated by the opportunity to improve scientific understanding and forecaster situational awareness of this class of snowstorms by means of a multiscale analysis. The multiscale analysis focuses on documenting: 1) the planetary-to-synoptic-scale flow patterns occurring prior to and during major transition season …

State Dependency Of The Forest-Tundra-Short Wave Feedback : Comparing The Mid-Pliocene And Pre-Industrial Eras Using A Newly-Developed Vegetation Model, Pablo Paiewonsky

Legacy Theses & Dissertations (2009 - 2024)

The forest-tundra-short wave feedback is the dominant short wave (SW) vegetation feedback at mid-to-high northern latitudes and is an important feedback in Earth’s climate system, especially due to its potential role in modulating glacial cycles. Little research has been done on how the strength of this feedback might vary with the background climate state. It is hypothesized that the feedback has generally strengthened over the last four million years. The feedback mechanism is hypothesized to be weaker under warm Northern Hemispheric conditions when tundra is primarily confined to the high Arctic than under cooler conditions in which the forest-tundra boundary …